Abstract Rationale Pneumocystis jirovecii is a fungal pathogen that causes respiratory infections, particularly in immunocompromised individuals such as children with oncologic diseases. Early recognition is critical, as the clinical and radiological presentation may mimic other causes of pneumonia. Diagnostic confirmation requires visualization of the microorganism by microscopy or polymerase chain reaction (PCR) in bronchoalveolar lavage (BAL) samples. Treatment with trimethoprim-sulfamethoxazole is highly effective. This study aimed to describe the clinical, radiological, and laboratory characteristics of pediatric oncology patients diagnosed with P. jirovecii respiratory infection. Methods We conducted a descriptive case series including 11 pediatric oncology patients admitted to HOMI (Hospital de la Misericordia, Bogotá, Colombia) between 2023 and 2024, in whom P. jirovecii infection was detected by PCR in BAL fluid. Demographic data, clinical presentation, oxygenation parameters, laboratory values, imaging findings, and outcomes were collected and analyzed. Results The mean age was 10 years (standard deviation SD 4.5), and six patients (54.5%) were male. Seven (63.6%) had acute lymphoblastic leukemia, and two (18.2%) were hematopoietic stem cell transplant recipients. The mean minimum oxygen saturation was 85.5% (SD 5.2%). Eight patients (72.7%) required admission to the pediatric intensive care unit, with four (46.4%) requiring invasive mechanical ventilation and seven (63.6%) high-flow nasal cannula. Lymphopenia was observed in eight patients; the median lymphocyte count was 464 cells/µL (interquartile range 228-1284). Chest computed tomography most commonly showed ground-glass opacities (10 patients, 90.9%) and micronodules (3 patients, 27.3%). Coinfections were frequent: six patients had cytomegalovirus and four had rhino/enterovirus detected in BAL. All patients received trimethoprim-sulfamethoxazole therapy. Conclusions Most pediatric oncology patients with P. jirovecii respiratory infection presented with severe illness, often requiring intensive respiratory support. Laboratory and imaging findings were consistent with previous reports, highlighting lymphopenia and ground-glass opacities as key features. Our data reinforce the need for high diagnostic suspicion of P. jirovecii infection in immunocompromised children presenting with severe pneumonia. Early molecular testing and prompt initiation of specific therapy remain essential to reduce morbidity and improve outcomes in this vulnerable population. This abstract is funded by: None
Restrepo et al. (Fri,) studied this question.